In the tire industry, the method for continuous monitoring of flat trac type equipment and force and moment (F&M) machines comprises repeated running of the machines and applying SPC (statistical processing control) analysis methods to monitor testing repeatability. This, together with routine machine calibration checks, provides fairly repeatable and consistent results. Cross-correlation between machines run in different locations, using similar type tires, however, showed significant differences between the machines. This is not a problem for individual machines since data for a specific test tire is usually compared to a control tire that is tested on the same machine. To correlate data from one machine to another, when the need arises, correlation regession equations have been developed wherein the data from one machine can be used to predict the correlating data on another machine.
There is a need in the art to standardize, as much as possible, different machines that are used to do the same type of testing. One means to do this is to provide a control tire, which has known and/or predictable properties, that can be used as a standard on all such testing machines. Then, as much as possible, the machines can be calibrated for the known properties of the control tire. While this may not eliminate the need for correlation regression equations, the differences between the machines can be reduced.
U.S. Pat. No. 2,945,525 describes an annular layer comprising ringed shaped reinforcing elements which have at least one interruption per each circumference of the tire. The layer described in the patent is a belt layer which is the sole reinforcement of the crown area of the tire.
It is an object of this invention to provide a control tire that has known, predictable and consistent properties.
Other objects of the invention will be apparent from the following description and claims.
Definitions
"Apex" refers to a wedge of rubber placed between the carcass and the carcass tumup in the bead area of the tire, usually used to stiffen the lower sidewall of the tire.
"Axial" and "axially" means lines or directions that are parallel to the axis of rotation of the tire.
"Bead" means that part of the tire comprising an annular tensile member wrapped by ply cords and shaped, with or without other reinforcement elements such as flippers, chippers, apexes, toe guards and chafers, to fit the design rim.
"Carcass ply" means the tire structure apart from the belt structure, tread, undertread, sidewall rubber and the beads.
"Equatorial plane (BP)" means the plane perpendicular to the tire's axis of rotation and passing through the center of its tread.
"Pantographing" refers to the shifting of the angles of cord reinforcement in a tire when the diameter of the tire changes, e.g. during the expansion of the tire in the mold.
"Ply" means a continuous layer of rubber-coated parallel cords.
"Pneumatic tire" means a mechanical device of generally toroidal shape (usually an open torus) having beads and a tread and made of rubber, chemicals, fabric and steel or other materials. When mounted on the wheel of a motor vehicle, the tire through its tread provides a traction and contains the fluid or gaseous matter, usually air, that sustains the vehicle load.
"Radial" and "radially" means directions radially toward or away from the axis of rotation of the tire.
"Radial-ply tire" means a belted or circumferentially restricted pneumatic tire in which the ply cords which extend from bead to bead are laid at cord angles between 65 to 90 degrees with respect to the equatorial plane of the tire.
"Sidewall" means that portion of a tire between the tread and the bead.
"Splice" refers to the connection of end of two components, or the two ends of the same component in a tire. "Splice" may refer to the abutment or the overlapping of two such ends.
"Tread" means a molded rubber component which, when bonded to a tire casing, includes that portion of the tire which comes into contact with the road when the tire is normally inflated and under normal load.